Motor vehicle clutch assembly having a hydraulic actuator which hydraulic actuator has a transmission

ABSTRACT

An actuator is provided with a drive system and a crank mechanism which converts the motion of the drive system into an essentially translational motion of an output element. The crank mechanism is designed as a worm gear pair with a worm gear which sits on the output shaft and is engaged with a segment worm gear which is rotationally mounted in a housing, whereby engaged with the segment worm gear, in addition to the output element, there is an energy storing device, preferably a spring device, mounted so that it can pivot in a bearing, which energy storing device can move relative to the segment worm gear. The spring device, in the relative position of the energy storing device with respect to the segment worm gear in which the distance between the bearing point of the energy storing device and its engagement with the segment worm gear is at a minimum, is brought closer with its end facing the segment worm gear, to within the gap width, to the outer edge of the segment worm gear, and when the worm gear is displaced around its axis of rotation, can be inserted in a recess which is located in the segment worm gear.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an actuator, in particularfor a motor vehicle friction clutch. The actuator includes a drivesystem and a crank mechanism, which crank mechanism converts the motionof the drive system into an essentially translational motion of anoutput element. The crank mechanism is designed as a worm gear pair withan input-side worm gear and a segment worm gear rotationally mounted ina housing. Engaged with the segment worm gear, in addition to the outputelement, there is an energy storing device, preferably a spring device,mounted so that it can pivot in a bearing, which energy storing devicecan move relative to the segment worm gear.

2. Background Information

German Patent No. 37 06 849 A1 discloses an actuator which has a drivesystem, the motion of which is converted into an essentiallytranslational motion of an output element by a crank mechanism. Thecrank mechanism is designed as a worm gear transmission with a worm gearwhich sits on the output shaft and is engaged with a segment worm gearwhich is rotationally mounted in a housing, whereby engaged with thesegment worm gear, in addition to the output element, is an energystoring device located so that it can pivot in a bearing point. Theenergy storing device has a spring device which is capable of movementrelative to the segment worm gear. Beyond a specified top dead centerposition, the spring device rebounds under relaxation, whereby therebound direction is selected so that it has at least a significantcomponent in the direction of displacement of the application spring ofthe clutch, which is designed as a hydraulic master cylinder, and can bedisplaced from its active position by a slave cylinder (not shown). Thespring device of the energy storing device thereby assists the drivesystem in its movement, so that the drive system can be designed to berelatively weak.

The energy storing device has a tappet rod which, by means of an eye,surrounds a bolt which is located in cheeks of the segment worm gearwhich are located at some distance from one another.

By means of the eye, the energy storing device thus extends into thetooth trace of the segment worm gear, but the tappet rod, in thedirection of the segment worm gear, extends far enough beyond the springdevice that the latter is always held, regardless of the degree ofdeformation of its spring, at some distance from the circumferentialarea of the cheeks and thus of the tooth trace of the segment worm gear.Thus, when there is a displacement movement of the segment worm gear bya predetermined angle, contact of the spring device against the edge ofthe segment worm gear as a result of the relaxation of the spring aftera displacement of the energy storing device from the top dead centerposition is prevented. However, one clear disadvantage of such arealization would appear to be that, on account of the great distance ofthe spring device from the edge of the segment worm gear, the energystoring device must generally be very long, which means that the housingwhich encloses this transmission mechanism must generally becorrespondingly large. Problems can result when the actuator isinstalled in motor vehicles, if the vehicles in question do not havesufficient space for the installation of such devices in the placesprovided for the purpose.

OBJECT OF THE INVENTION

The object of the present invention is to improve an actuator so that,while it includes an energy storing device, which energy storing deviceassists the drive mechanism and is engaged with a segment worm gear, theactuator also occupies only a minimal amount of space.

SUMMARY OF THE INVENTION

The present invention teaches that this object can be accomplished, inaccordance with at least one preferred embodiment, by designing theenergy storing or spring device and, in particular, the end of thespring device facing the segment worm gear, to track the movement of thesegment worm gear. The segment worm gear, in the area in which thesegment worm gear can pass the energy storing device during rotationalmovement of the segment worm gear, can preferably be provided with arecess. The angular position and radially inward dimension of the recesscan be designed so that the spring device, during the displacementmotion of the energy storing device, can be inserted into this recess,without the energy storing device thereby coming into contact with thesegment worm gear radially inwardly or at the limits of the recess inthe circumferential direction. Consequently, since the spring device canbe inserted inside the tooth trace of the segment worm gear, the springdevice can be brought very close to the axis of rotation of the segmentworm gear. As a result, the bearing point of the energy storing devicecan be shifted toward the segment worm gear by the distance whichcorresponds to the depth of insertion in the recess. Thus, without anyrestriction of the function of the energy storing device, the housing,which can enclose the energy storing device, can be made shorter in thelongitudinal direction of the energy storing device by the distance bywhich the energy storing device can be brought closer to the axis ofrotation of the segment worm gear, due to the recess in the segment wormgear.

The recess can preferably be provided with limits in the circumferentialdirection so that the segment worm gear can essentially only bedisplaced by a specified angle of rotation. After the segment worm gearreaches a limit position in the direction of displacement, the segmentworm gear can be returned to the starting position of the segment wormgear, by the drive system, which drive system can preferably beconnected with the actuator, essentially as soon as the drive systemreceives an indication of the intention to change the position of theclutch, e.g. for engagement or disengagement.

Each of the above-mentioned limits of the segment worm gear canpreferably correspond to a stop, which stop can limit the angulardisplacement of the segment worm gear. This stop can be located in astationary manner in the housing and the stop can project into a recessof the segment worm gear. This measure can also contribute to keepingthe housing of the actuator as small as possible, since inside the toothtrace of the segment worm gear, in the longitudinal area of the recess,the segment worm gear can have rotation limits on its ends, viewed inthe circumferential direction. The rotation limits of the segment wormgear can interact with the stop of the present invention. In anadvantageous realization of this stop, the contact between the stop andthe elastomer covering of the stop can damp the drift movement of thesegment worm gear.

Another embodiment of the present invention can also contribute to acompact design of the segment worm gear transmission and thus of thehousing, in that, due to the one-piece design of the hub and cheeks ofthe segment worm gear, there can essentially be no need for additionalconnecting means, which additional connecting means would also take upspace. In accordance with such an embodiment, the number of requiredcomponents can also be significantly reduced, and can thus also reducethe number of possible sources of error.

As a result of another advantageous feature, the action of the springdevice of the energy storing system can be used to fix both the energystoring device and the output element in their corresponding locations.The output element can include, for example, a hydraulic mastercylinder. Thus, on one hand, when assembling the segment worm geartransmission, it is possible to employ a connection between the notch ofthe energy storing system (for example, an eye with a bolt) and thesegment worm gear. On the other hand, it is possible to employ aconnection between the segment worm gear and a notch of the outputelement, for example, also in the form of an eye with a bolt. As aresult of such connections, the respective notch can be engaged in therespective locator under the action of the spring device of the energystoring mechanism and can be held in this position by the spring device.In this regard, however, it should be noted that the rotational mobilityof the segment worm gear can be restricted, so that both the notch ofthe energy storing device and also the notch of the output element canessentially always be oriented so that the spring device of the energystoring device can perform its retaining function.

Although the bolt, by means of which the energy storing device can beconnected to the segment worm gear, can preferably be permanentlyattached to the energy storing device (for example, by extrusion coatingwith plastic, for reasons of safety) each end of the bolt can also havea device for preventing the bolt from falling out. This device toprevent the bolt from falling out can preferably include a correspondingconfiguration of at least one of the cheeks for locating the bolt. Itis, however, also conceivable that the bolt can be extended in the axialdirection so that the bolt can almost touch the bottom of the housing,in which housing the worm gear transmission can be located. In thatcase, the above-mentioned bottom of the housing can act to essentiallyprevent the bolt from falling out.

In another preferred embodiment, as a result of the mounting of thebearing pin, which bearing pin can support the segment worm gear on oneside in the housing, the segment worm gear can also be short in theaxial direction of this bearing neck. Consequently, the housing in whichthe worm gear transmission is located can also be made essentiallycompact in the corresponding axial direction. In an embodiment in whichthe segment worm gear can be mounted so that the segment worm gear canslide on a stationary bearing neck, the segment worm gear can be madeout of plastic. As a result, the friction between the inside of the huband the bearing neck can be minimal. When the segment worm gear is madeof plastic, it can also be particularly suitable if it is made in onepiece, i.e. with regard to the hub and the cheeks.

In accordance with another embodiment of the present invention, thecrank mechanism of the actuator can be constructed with essentially thesmallest possible number of components. A particularly advantageousfeature includes the design of the locator, which locator can make itpossible to position the corresponding notch from radially outside toradially inside in the segment worm gear. To permit the positioning ofthis notch, the bearing shell can be designed so that the bearing shellcan enclose the notch only over a portion of the circumference of thenotch. Because the locators and a portion of the segment worm gear,which portion can surround the bearing neck, are made of elastomermaterial, there is essentially no abrasion of the element located by thesegment worm gear if there is a relative movement between the elementand the segment worm gear. The optimal solution can be a one-piecedesign of the segment worm gear made of elastomer material, since it isa one-piece design of the segment worm gear can permit less weight,economical manufacturing and the combination of all the transmission andbearing functions in a single component with relatively little designeffort or manufacturing expense.

When the word "invention" is used in this specification, the word"invention" includes "inventions", that is, the plural of "invention".By stating "invention", the Applicants do not in any way admit that thepresent application does not include more than one patentably andnon-obviously distinct invention, and maintains that this applicationmay include more than one patentably and non-obviously distinctinvention. The Applicants hereby assert that the disclosure of thisapplication may include more than one invention, and, in the event thatthere is more than one invention, that these inventions may bepatentable and non-obvious one with respect to the other.

One aspect of the present invention resides broadly in a hydraulicallyoperated clutch assembly for a motor vehicle, the clutch assemblycomprising: a flywheel having an axis of rotation and defining an axialdirection parallel to the axis of rotation; a clutch disc; a pressureplate for applying an axially directed force to the clutch disc, withrespect to the axis of rotation of the flywheel, to engage the clutchdisc with the flywheel; the clutch disc being disposed between theflywheel and the pressure plate; the clutch disc comprising frictionlining means for contacting the pressure plate and the flywheel duringengagement of the clutch disc with the flywheel; means for hydraulicallyactivating the clutch disc; the hydraulic activating means comprising:chamber means, the chamber means having a first end and a second end, atleast a portion of the chamber means containing hydraulic fluid therein;means for being acted upon by the hydraulic fluid; the means for beingacted upon by the hydraulic fluid being disposed in the chamber means;means for operatively connecting the pressure plate to the means forbeing acted upon by the hydraulic fluid; means for providing hydraulicfluid into and out of the chamber means to activate the pressure plate;means for actuating the hydraulic activating means; the actuating meanscomprising: a housing; a mechanical drive mechanism for converting afirst geometric movement into a second geometric movement; means fordriving the mechanical drive mechanism; the driving means beingconnected to the mechanical drive mechanism; means for providing signalsto the mechanical drive mechanism; means for connecting the means forproviding signals with the mechanical drive mechanism; the signals foroperating the mechanical drive mechanism; cylinder means for providinghydraulic fluid under pressure to the means for providing hydraulicfluid into and out of the chamber means; the mechanical drive mechanismbeing connected to the cylinder means to provide flow of hydraulic fluidinto and out of the chamber means; the mechanical drive mechanismcomprising: worm gear means; the worm gear means comprising a worm gear;the worm gear means further comprising worm gear wheel means; the wormgear wheel means being in mesh with the worm gear; the worm gear wheelmeans being connected within the housing; the worm gear wheel meansbeing movable in a first direction and a second direction; the worm gearwheel means having an outer circumferential portion; at least a portionof the worm gear wheel means comprising a cut out portion; a coil springstructure; the coil spring structure being disposed within the housing;the coil spring structure being disposed adjacent the worm gear wheelmeans; the coil spring structure having a first end and a second end;the first end of the coil spring structure comprising pivot means; thehousing comprising mating pivot means for receiving the pivot means ofthe coil spring structure; the pivot means of the coil spring structuretogether with the mating pivot means of the housing to permit the coilspring structure to pivot with respect to the worm gear wheel means; thesecond end of the coil spring structure being disposed opposite thefirst end; the second end of the coil spring structure being disposedadjacent a portion of the worm gear wheel means; the worm gear wheelmeans being movable in the first direction to dispose the second end ofthe coil spring structure in contact with the outer circumferentialportion of the worm gear wheel means; and the worm gear wheel meansbeing movable in the second direction to dispose a portion of the coilspring structure within the cut out portion of the worm gear wheelmeans.

Another aspect of the present invention resides broadly in an actuatorfor actuating a hydraulic activating system, such as an actuator foroperating a hydraulically operated clutch assembly for a motor vehicle,which clutch assembly comprises: a flywheel having an axis of rotationand defining an axial direction parallel to the axis of rotation; aclutch disc; a pressure plate for applying an axially directed force tothe clutch disc, with respect to the axis of rotation of the flywheel,to engage the clutch disc with the flywheel; the clutch disc beingdisposed between the flywheel and the pressure plate; the clutch disccomprising friction lining means for contacting the pressure plate andthe flywheel during engagement of the clutch disc with the flywheel; thehydraulic activating system comprising: chamber means, the chamber meanshaving a first end and a second end, at least a portion of the chambermeans containing hydraulic fluid therein; means for being acted upon bythe hydraulic fluid; the means for being acted upon by the hydraulicfluid being disposed in the chamber means; means for operativelyconnecting the pressure plate to the means for being acted upon by thehydraulic fluid; means for providing hydraulic fluid into and out of thechamber means to activate the pressure plate; the actuator for actuatingthe hydraulic activating system comprising: a housing; a mechanicaldrive mechanism for converting a first geometric movement into a secondgeometric movement; means for driving the mechanical drive mechanism;the driving means being connected to the mechanical drive mechanism;means for providing signals to the mechanical drive mechanism; means forconnecting the means for providing signals with the mechanical drivemechanism; the signals for operating the mechanical drive mechanism;cylinder means for providing hydraulic fluid under pressure to the meansfor providing hydraulic fluid into and out of the chamber means; themechanical drive mechanism being connected to the cylinder means toprovide flow of hydraulic fluid into and out of the chamber means; themechanical drive mechanism comprising: worm gear means; the worm gearmeans comprising a worm gear; the worm gear means further comprisingworm gear wheel means; the worm gear wheel means being in mesh with theworm gear; the worm gear wheel means being connected within the housing;the worm gear wheel means being movable in a first direction and asecond direction; the worm gear wheel means having an outercircumferential portion; at least a portion of the worm gear wheel meanscomprising a cut out portion; a coil spring structure; the coil springstructure being disposed within the housing; the coil spring structurebeing disposed adjacent the worm gear wheel means; the coil springstructure having a first end and a second end; the first end of the coilspring structure comprising pivot means; the housing comprising matingpivot means for receiving the pivot means of the coil spring structure;the pivot means of the coil spring structure together with the matingpivot means of the housing to permit the coil spring structure to pivotwith respect to the worm gear wheel means; the second end of the coilspring structure being disposed opposite the first end; the second endof the coil spring structure being disposed adjacent a portion of theworm gear wheel means; the worm gear wheel means being movable in thefirst direction to dispose the second end of the coil spring structurein contact with the outer circumferential portion of the worm gear wheelmeans; and the worm gear wheel means being movable in the seconddirection to dispose a portion of the coil spring structure within thecut out portion of the worm gear means.

Yet another aspect of the present invention resides broadly in ahydraulically operated clutch assembly for a motor vehicle, the clutchassembly comprising: a flywheel having an axis of rotation and definingan axial direction parallel to the axis of rotation; a clutch disc; apressure plate for applying an axially directed force to the clutchdisc, with respect to the axis of rotation of the flywheel, to engagethe clutch disc with the flywheel; the clutch disc being disposedbetween the flywheel and the pressure plate; the clutch disc comprisingfriction lining means for contacting the pressure plate and the flywheelduring engagement of the clutch disc with the flywheel; means forhydraulically activating the clutch disc; the hydraulic activating meanscomprising: chamber means, the chamber means having a first end and asecond end, at least a portion of the chamber means containing hydraulicfluid therein; means for being acted upon by the hydraulic fluid; themeans for being acted upon by the hydraulic fluid being disposed in thechamber means; means for operatively connecting the pressure plate tothe means for being acted upon by the hydraulic fluid; means forproviding hydraulic fluid into and out of the chamber means to activatethe pressure plate; means for actuating the hydraulic activating means;the actuating means comprising: a housing; a mechanical drive mechanismfor converting a first geometric movement into a second geometricmovement; means for driving the mechanical drive mechanism; the drivingmeans being connected to the mechanical drive mechanism; means forproviding signals to the mechanical drive mechanism; the signals foroperating the mechanical drive mechanism; cylinder means for providinghydraulic fluid under pressure to the means for providing hydraulicfluid into and out of the chamber means; the mechanical drive mechanismbeing connected to the cylinder means to provide flow of hydraulic fluidinto and out of the chamber means; the mechanical drive mechanismcomprising: worm gear means; the worm gear means comprising a worm gear;the worm gear means further comprising worm gear wheel means; the wormgear wheel means being in mesh with the worm gear; the worm gear wheelmeans being connected within the housing; the worm gear wheel means forbeing moved in a first direction and a second direction; the worm gearwheel means having an outer circumferential portion; the worm gear wheelmeans comprising at least one notch; at least one member for beingengaged within the at least one notch; the at least one notch having aninner circumferential portion; the at least one member, engaged withinthe at least one notch, having an outer circumference; a portion of theouter circumference of the at least one member engaged within the atleast one notch being in contact with a portion of the innercircumferential portion of the at least one notch; the innercircumferential portion of the at least one notch being insufficient byitself to hold the at least one member within the at least one notch;means for retaining the at least one member within the at least onenotch of the worm gear wheel means; and the means for retaining the atleast one member within the at least one notch being disposed within thehousing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is explained in greater detail below withreference to the accompanying drawings, in which:

FIG. 1 shows an overhead view in partial cross section of an electricmotor actuator for a motor vehicle friction clutch;

FIG. 2 shows the actuator as shown in FIG. 1 along Line II--II; and

FIG. 3 shows a cross section through the actuator, viewed along LineIII--III in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 to 3 illustrate an actuator for a motor vehicle friction clutch,which friction clutch, in the illustrated embodiment, can have ahydraulic clutch disengagement system. The actuator includes a housing 1with a drive system 4 in the form of an electric motor 5. The electricmotor 5 can actuate an output element 2 formed by a hydraulic mastercylinder 9 of the hydraulic clutch disengagement system by means of atransmission 7. The transmission 7 can preferably be designed as a crankmechanism.

The crank mechanism or transmission 7 can act as a worm gear pair 8,which worm gear pair 8 can have a segment worm gear 10. The segment wormgear 10 can be rotationally mounted on a bearing neck 11, which bearingneck 11 can be fastened by its one end in the housing part 1. A wormgear 15 can sit directly on an output shaft 14 of the drive system 4,which worm gear 15 can be engaged with a worm gear thread 13 on thecircumference of the segment worm gear 10. The drive shaft 14 can bemounted, with its free end, in the housing part 1 by means of a sleeve17. On the segment worm gear 10 there can preferably be cheeks 18, whichcheeks 18, viewed in the axial direction of the bearing neck 11, can belocated at some distance from one another. In the cheeks 18, there canbe first recesses 20, which first recesses 20 can preferably be alignedwith one another. There can be a bolt 21 located within the recesses 20,which bolt 21 can run parallel to the bearing neck 11. The bolt 21 canbe inserted and fastened in an eye 60 of a tappet rod 22, whereby theeye 60 is preferably made of plastic and the eye 60 can be permanentlyconnected to the bolt 21 by extrusion coating of the bolt 21. The tappetrod 22 can be located so that it can be displaced in a plastic bushing27.

The plastic bushing 27 can be mounted with its end farther from the bolt21 so that the plastic bushing 27 can pivot in a bearing 85 in thehousing 1. The plastic bushing 27 can have a seat 61 for a spring 62,which spring 62 can be supported with its end facing the segment wormgear 10 on a spring plate 25. The spring plate 25 can come into contact,by means of its side farther from the spring 62, with a radiallyexpanded shoulder 26 of the tappet rod 22.

An energy storing device 23 can be formed by the plastic bushing 27,together with the tappet rod 22 (surrounding the bolt 21), along withthe spring 62, and the spring plate 25. The bearing point 85 of theenergy storing device 23 on the housing 1 can be located relative to thecenter axis of the bearing neck 11. Thus, the energy storing device 23,in its limit position as shown in FIG. 1, can assume a position slightlypast top dead center opposite to the disengagement direction of rotationof the segment worm gear 10. Such a position past top dead center tostabilize the limit position is described in detail in German Patent No.37 06 849 A1.

The segment worm gear 10, which segment worm gear 10 can preferablyinclude the hub 65, a carrier 66 for the gear teeth 13 and the cheeks18, can preferably be made in one piece out of plastic. The segment wormgear 10 can have, with reference to the longitudinal axis of the bearingneck 11 in FIG. 1, a recess 68 in the counterclockwise direction insidethe tooth trace of the segment worm gear 10. The recess 68, viewed inthe circumferential direction, can be formed between limits 35 and 36 ofthe segment worm gear 10. This recess 68, as explained in greater detailbelow, can act, when the segment worm gear 10 is driven in the directionof rotation, illustrated in FIG. 1, in the clockwise direction to insertthe spring device 63.

In summary, in accordance with an embodiment of the present invention,the segment worm gear 10 preferably includes the hub 65, a carrier 66for the gear teeth 13, and the cheeks 18. The segment worm gear 10,along with the hub 65, the carrier 66, and the cheeks 18 are preferablymade in one piece out of plastic. The cheeks 18 preferably include solidportions, which solid portions extend outward and rotate around the hub65 of the segment worm gear 10. With reference to the longitudinal axisof the bearing neck 11, as illustrated in FIG. 1, the segment worm gear10 can preferably have a recess 68, which recess 68 can be located tothe right of the gear teeth 13 of the segment worm gear 10, with respectto FIG. 1. The recess 68 can be located in a portion of thecircumference of the segment worm gear 10 between the limits 35 and 36.When the segment worm gear 10 is rotated essentially in thecounterclockwise direction, with respect to FIG. 1, the recess 68 canprovide a space in which the spring device 63 can be inserted. The endof the spring device 63 facing the recess 68 can thereby be in contactwith limit 35 of the segment worm gear 10. As a result, the springdevice 63 can exert an additional force on the segment worm gear 10thereby providing an essentially quick rotation of the segment worm gear10.

At an angular offset with respect to the center axis of the bearing neck11, there can be additional recesses 28 (as shown in FIG. 3) in thecheeks 18 of the segment worm gear 10, which additional recesses 28 canpreferably be aligned with one another. These additional recesses 28 canbe provided to hold a bolt 29, which bolt 29 can be surrounded by an eye30 of the piston rod 31 of the hydraulic master cylinder 9. Theadditional recesses 28 can be oriented toward the energy storing device23, so that the bolt 29, once it has been introduced from radiallyoutside into the recesses 28, can be held by the action of the energystoring device 23 on the radially inner end of the recesses 28. Theangle of rotation of the segment worm gear 10 can thereby be limited sothat this advantageous action of the energy storing device 23 can bepreserved under essentially all conditions.

In summary, in accordance with an embodiment of the present invention,due to the spring action of the energy storing device 23, the bolt 29can be essentially force fit radially within the recesses 28 of theplastic material of the segment worm gear 10. For this purpose, theangle of rotation of the segment worm gear 10 is preferably limited,thus permitting the frictional spring action of the energy storingdevice 23 to essentially always be exerted on the bolt 29 within therecesses 28.

The eye 60, of the energy storing device 23, can surround the bolt 21.The eye 60 can form a first notch 70 on the segment worm gear 10. Theeye 30, which eye 30 can surround the bolt 29, can form a second notch71. The first notch 70 can extend into a bearing shell 90 of therecesses 20, which recesses 20 act as a locator 72 while the notch 71can be engaged in a bearing shell 91 of the locator 73 formed by therecesses 28. The bearing shells 90 and 91 can surround the bolts 21 and29, respectively, over only a portion of the diameter of the bolts 21and 29. Thus, it can be possible, as explained in greater detail below,to engage the notches 70, 71 in the locators 72, 73, respectively, fromradially outside to radially inside. In the vicinity of the respectivelocator 72, 73, the upper cheek 18, illustrated in FIG. 1, can have acover plate 74. By means of the cover plate 74, should the bolts 21 and29 unintentionally come loose from the corresponding eyes 60 and 30, thebolts 21 and 29 can be prevented from falling out. On the opposite sideof the bolts 21 and 29, the bolts 21 and 29 can preferably extend, towithin the gap width, toward the base 75 of the housing 1, so that here,the bolts 21 and 29 can be protected from falling out of thecorresponding eyes 60, 30. The cover plate 74 of the upper cheek 18,thus, like the base 75 of the housing 1, can act as a device 76 toessentially prevent the bolts 21 and 29 from falling out.

In accordance with an embodiment of the present invention, therefore,the bolts 21 and 29 can preferably have a long enough dimension suchthat one end of the bolts 21 and 29 can extend toward, and are incontact with, the cover plate 75 of the upper part of the cheeks 18,while the other end of the bolts 21 and 29 can extend toward, and are incontact with, the base 75 of the housing 1. The cover plate 74 togetherwith the base 75 can thereby surround and securely hold the respectiveends of the bolts 21 and 29 in place with respect to the segment wormgear 10.

In the base 75 of the housing 1, a bolt 78 can be fastened. The bolt 78can be provided, at least in the longitudinal area of a recess 79 in thesegment worm gear 10, with an elastic covering 80. This bolt 78 can actas a stop 81 for the ends of the recess 79 which lie inside the toothtrace of the segment worm gear 10, viewed in the circumferentialdirection.

In summary, in accordance with an embodiment of the present invention,the bolt 78 can act as the stop 81 for the segment worm gear 10 as thesegment worm gear 10 rotates in a clockwise or counterclockwisedirection with respect to FIG. 1.

The transmission can function as follows, in accordance with at leastone embodiment of the present invention:

A motion imparted by the drive system 4 can cause a rotation of theoutput shaft 14, so that a worm gear 15 located on the drive shaft 14,and thus the segment worm gear 10, can be placed in rotational motion.As a function of the direction of the drive 4, the piston rod 31 of thehydraulic master cylinder 9 can be moved inward or outward. The energystoring device 23 can thereby act as follows:

In the limit position of the segment worm gear 10 corresponding to theengaged position of the clutch, as illustrated in FIG. 1, the spring 62is essentially taut. If the drive system 4 propels the segment worm gear10 in the clutch disengagement direction, i.e. counterclockwise, withrespect to FIG. 1, the spring 62 is essentially relaxed after the spring62 passes through its top dead center position. Thus, the spring 62 canassist the drive 4. In this manner, the clutch can be disengagedquickly, even when the drive mechanism is comparatively weak. In theengagement direction, the drive system 4, the direction of rotation ofwhich has been reversed, i.e. clockwise with respect to FIG. 1, can beassisted by the clutch application spring, so that in spite of thecomparatively low power of the drive system, tension can once again beapplied to the spring 62.

In summary, in accordance with an embodiment of the present invention,the power of the drive 4 can permit rotation of the drive shaft 14 inone direction, or, alternatively, in another direction. The threads ofthe worm gear 15 of the drive shaft 14 can thereby come into contactwith the worm gear threads 13 of the segment worm gear 10. As a result,the segment worm gear 10 can rotate in a direction corresponding to thedirection of rotation of the drive shaft 14. The piston rod 31 canpreferably be fastened to the segment worm gear 10, thereby permittingthe piston rod 31 to move in a longitudinal direction with respect tothe transmission 7. The piston rod 31 can thereby move inward or outwardwith respect to the hydraulic master cylinder 9. When the clutch is inthe engaged position, the segment worm gear 10 is essentially in itslimit position, as shown in FIG. 1. In the limit position of the segmentworm gear 10, the energy storing device 23 can preferably be taut withthe tension applied thereto. When the drive 4 rotates the segment wormgear 10 in the opposite direction, i.e. counterclockwise with respect toFIG. 1, the clutch can become disengaged. As the clutch begins todisengage, the energy storing device 23 can become relaxed, thusessentially assisting in the quick disengagement of the clutch.

While the energy storing device 23 can assist the drive motion of thedrive system 4, the energy storing device 23 can follow the rotationalmovement of the segment worm gear 10 by means of a pivoting movementaround the bearing point 85 in the housing 1. Thereby the spring device63 and, in particular, the spring plate 25 and the end of the spring 62facing the spring plate 25, can thereby pivot into the recess 68 of thesegment worm gear 10, due to the change in the angle of rotation withrespect to the segment worm gear 10. The recess 68 can thereby bedesigned so that the spring device 63 can penetrate inside the toothtrace of the segment worm gear 10, without the spring plate 25 or thespring 62 essentially coming in contact with the corresponding limit 35,36 of the recess 68.

As a result of this feature, the spring plate 25 and thus the entireenergy storing system 23 can be installed so close to the segment wormgear 10 that when the energy storing system 23 passes through the topdead center position, in which the spring 62 is compressed to themaximum, the spring plate 25 can be moved close to the circumferentialarea of the segment worm gear 10, to within the gap width. The housing 1can thus be kept very compact in the direction of the longitudinal axisof the energy storing system 23. When the spring 62 essentially relaxesduring a pivoting movement of the segment worm gear 10, the spring plate25 can be pushed toward the bearing neck 11. The spring plate 25 canthus penetrate into the recess 68.

Also for reasons of space, the stop 81 can be engaged in the recess 79.The recess 79, like the recess 68, can preferably be located inside thetooth trace of the segment worm gear 10. The recess 79, seen in thecircumferential direction, can preferably be adapted to the size of thepivoting angle of the segment worm gear 10, so that when thepredetermined angle is exceeded, the segment worm gear 10 canessentially always be in contact with one end of the recess 79 againstthe stop 81. The same can be true for a motion in the oppositedirection.

In summary, in accordance with an embodiment of the present invention,the stop 81 can preferably be located within the space defined by therecess 79, thereby also permitting a compact design of the housing 1, inthe longitudinal direction. The recess 79 can preferably be designed toessentially surround the angle of rotation of the segment worm gear 10.The stop 81, however, can preferably be located at a point within theouter circumference of the segment worm gear 10. As a result, thesegment worm gear 10 can rotate, i.e. in a clockwise or counterclockwisedirection with respect to FIG. 1, whereby a circumferential portion ofthe segment worm gear 10 can come into contact with the correspondingside of the stop 81, which stop 81 can thereby prevent the segment wormgear 10 from exceeding the predetermined angle of rotation.

As a result of the one-piece design of the segment worm gear 10, withregard to its carrier 66 for the gear teeth 13, its hub 65 and itscheeks 18, large connecting means which take up a great deal of spaceare essentially unnecessary. Also as a result of this one-piece design,the installation space made available by the housing 1 can be keptrelatively small. The size of the housing 1 can be further reduced bythe feature whereby the bearing neck 11, which bearing neck 11 can holdthe segment worm gear 10, can be fastened to the housing 1 on only oneside of the housing 1.

Since the segment worm gear 10 can be rotationally mounted on thisbearing neck 11, the segment worm gear 10 can preferably be made ofplastic, to prevent any unnecessary abrasion between the inside of thehub 65, of the segment worm gear 10, and the bearing neck 11. Preciselyas a result of the manufacture of the segment worm gear 10 out ofplastic, it becomes essentially possible to reduce the size of thetransmission 7 to a minimum.

As a result of the one-piece design of the segment worm gear 10, thenumber of components can be significantly reduced with respect to amulti-part design, e.g. like the one disclosed in DE 37 06 849 A1, sothat the manufacturing process can be very simple. This simplificationcan also be promoted by the fact that the notches 70 and 71, of theenergy storing system 23, and the piston rod 31, of the master cylinder9, respectively, can be engaged in a very simple manner in thecorresponding locators 72, 73, as follows:

When the energy storing system 23 is essentially not yet active, thesegment worm gear 10 can be pivoted in the counterclockwise directionuntil the piston rod 31 of the master cylinder 9 can be inserted in astraight line with its bolt 29 in the eye 30 into the recesses 28 of thecheeks 18. Then the segment worm gear 10 can be pivoted clockwise,driving the piston rod 31, until the recesses 20 in the cheeks 18 areessentially aligned with the longitudinal axis of the tappet rod 22 ofthe energy storing system 23. When the spring 62 relaxes, the bolt 21,held on the free end of the tappet rod 22 by means of the eye 60, can bepushed into the corresponding recesses 20 in the cheeks 18 of thesegment worm gear 10. Under the action of the now partly relaxed spring62, the bolt 21 can be held in contact with the radially inside end ofthe recesses 20. In this position of the segment worm gear 10, the otherlocator 73 can point toward the energy storing system 23, so that thelocator 73 can have a component against the direction of action of thespring 62.

The energy storing system 23 can also provide for contact of the bolt 29with the radially inner end of the recesses 28 in the cheeks 18 of thesegment worm gear 10. The energy storing system 23 can therefore beactive as a retaining element 92 for the notches 70, 71 on the bearingshells 90, 91 of the locators 72, 73. Thus the assembly regarding thesecomponents is essentially already complete.

In summary, in accordance with an embodiment of the present invention,an essentially simplified manufacture of the segment worm gear 10 caninclude the connection of the piston rod 31 and the energy storingdevice to the segment worm gear 10. Before the energy storing device 23is connected to the segment worm gear 10, the piston rod 31 canpreferably be connected to the segment worm gear 10. By rotating thesegment worm gear 10 in the counterclockwise direction, with respect toFIG. 1, the recesses 28 can extend in a radial direction with respect tothe piston rod 31. As a result, the bolt 29 can be inserted into the eye30 of the piston rod 31, then the bolt 29 can be inserted from radiallyoutside to radially within the recesses 28. Thereafter, the energystoring system 23 can be connected to the segment worm gear 10. Thus,the segment worm gear 10 is then rotated in the clockwise direction,with respect to FIG. 1, such that the recesses 20 can be in alignmentwith the tappet rod 22 of the energy storing system 23. The bolt 21 canthen be inserted into the eye 60 of the tappet rod 22 whereby the actionof the spring 62 of the energy storing system 23 can push the bolt 21radially within the recesses 20.

During the subsequent operation of the segment worm gear 10, the stop81, among other components, can essentially guarantee that the angle ofrotation of the segment worm gear 10 can be limited so that neither thenotch 70 nor the notch 71 can move out of the locators 72 or 73,respectively.

One feature of the invention resides broadly in the actuator, inparticular for a motor vehicle friction clutch, with a drive system anda crank mechanism which converts the motion of the drive system into anessentially translational motion of an output element, whereby the crankmechanism is designed as a worm gear pair with an input-side worm gearand a segment worm gear which is rotationally mounted in a housing,whereby engaged with the segment worm gear, in addition to the outputelement, there is an energy storing device, preferably a spring device,mounted so that it can pivot in a bearing, which energy storing devicecan move relative to the segment worm gear, characterized by the factthat the spring device 63, in the relative position of the energystoring device 23 with respect to the segment worm gear 10 in which thedistance between the bearing point 85 of the energy storing device 23and its engagement 70 with the segment worm gear 10 is at a minimum, isbrought closer with its end facing the segment worm gear 10, to withinthe gap width, to the outer edge of the segment worm gear 10, and whenthe worm gear is displaced around its axis of rotation, the springdevice can be inserted in a recess 68 which is located in the segmentworm gear 10 inside its tooth trace.

Another feature of the invention resides broadly in the actuator with asegment worm gear which can be displaced for a predetermined angle ofrotation, characterized by the fact that in the circumferentialdirection, the recess 68 is sized so that contact between the end of thespring device 63 facing the segment worm gear 10 and the limit 35, 36 onthe segment gear wheel corresponding to the direction of displacementcan be prevented.

Yet another feature of the invention resides broadly in the actuatorwith at least one stop which limits the angle of displacement of thesegment worm gear, whereby the stop is located in a stationary manner inthe housing and projects into a recess of the segment worm gear which islocated radially inside its tooth trace and is sized in thecircumferential direction so that its ends define the maximum angle ofdisplacement of the segment worm gear, characterized by the fact thatthe stop 81 is formed by a pivot 78 which is at least partly realizedwith an elastomer covering 80.

Still another feature of the invention resides broadly in the actuatorwith a segment worm gear which has a hub surrounding the axis ofrotation and two cheeks preferably running parallel to one another andat some distance from one another which are used to locate the notch ofthe energy storing device or of the output element, characterized by thefact that the hub 65 is designed in one piece with the cheeks 18.

A further feature of the invention resides broadly in the actuatorcharacterized by the fact that the cheeks 18 have locators 72, 73 bothfor the notch 70 of the energy storing device 23 and for the notch 71 ofthe output element 2, whereby the longitudinal direction of the locators72, 73 is selected so that they have a component opposite to thedirection of action of the energy storing device 23.

Another feature of the invention resides broadly in the actuatorcharacterized by the fact that the notches 70, 71 of the energy storingdevice 23 and of the output element 8 are each surrounded by an eye 60,30 respectively on the free end of a rod tappet rod 22, piston rod 31,in which bolts 21, 29 are engaged in the corresponding locators 72, 73.

Yet another feature of the invention resides broadly in the actuatorcharacterized by the fact that at least the eye 60 on the free end ofthe tappet rod 22 of the energy storing device 23 holds the bolt 21immovably in position.

Still another feature of the invention resides broadly in the actuatorcharacterized by the fact that the non-detachable connection between theeye 60, 30 and the bolt 21, 29 can be formed by extrusion-coating thelatter, preferably with plastic.

A further feature of the invention resides broadly in the actuatorcharacterized by the fact that there is a device 76 which keeps the boltcaptive corresponding to each end of the bolt 21, 29.

Another feature of the invention resides broadly in the actuatorcharacterized by the fact that at least one of the cheeks 18 has a coverplate 74 which is adjacent to the corresponding end of the bolt 21, 29as a device 76 to keep the bolt captive.

Yet another feature of the invention resides broadly in the actuatorcharacterized by the fact that the part of the bottom 75 of the housing1 which lies in the area of movement of the bolt 21, 29 acts duringdisplacement of the segment worm gear 10 as the device 76 to keep thebolt 21, 29 captive.

Still another feature of the invention resides broadly in the actuatorcharacterized by the fact that the segment worm gear 10 is mountedrotationally on a bearing neck 11, only one end of which is fastened inthe housing 1.

A further feature of the invention resides broadly in the actuatorcharacterized by the fact that the segment worm gear 10 is made ofplastic.

Another feature of the invention resides broadly in the actuator, inparticular for a motor vehicle friction clutch, with a drive system anda crank mechanism which converts the motion of the drive system into anessentially translational motion of an output element, whereby the crankmechanism is designed as a worm gear pair with an input-side worm and asegment worm gear which is rotationally mounted in a housing, whichsegment worm gear has a locator at least for the output element,characterized by the fact that the locator 72, 73 acts as a bearingpoint for a notch 70, 71, which after being inserted from radiallyoutside to radially inside into the locator 72, 73, can be brought intocontact against a bearing shell 90, 91 which encloses the locator overonly a portion of its circumference, and can be secured by a retainingelement 92 against falling out of the bearing shell 90, 91.

Yet another feature of the invention resides broadly in the actuatorcharacterized by the fact that at least the locator 72, 73 of thesegment worm gear 10 consists of elastomer material.

Still another feature of the invention resides broadly in the actuatorcharacterized by the fact that the hub 65 of the segment worm gear 10consists of elastomer material, and surrounds a bearing neck 11 which isfastened only on one end in the housing 1.

A further feature of the invention resides broadly in the actuatorcharacterized by the fact that the segment worm gear 10 is made in onepiece of elastomer material.

Another feature of the invention resides broadly in the actuatorcharacterized by the fact that the retaining element 92 is formed by anenergy storing device 23 which acts on the segment worm gear 10.

The components disclosed in the various publications, disclosed orincorporated by reference herein, may be used in the embodiments of thepresent invention, as well as, equivalents thereof.

The appended drawings in their entirety, including all dimensions,proportions and/or shapes in at least one embodiment of the invention,are accurate and to scale and are hereby included by reference into thisspecification.

All, or substantially all, of the components and methods of the variousembodiments may be used with at least one embodiment or all of theembodiments, if more than one embodiment is described herein.

Some examples of electronic components which may be utilized inaccordance with the present invention may be found in the following U.S.Patents: U.S. Pat. No. 5,325,082 entitled "Comprehensive VehicleInformation Storage System"; U.S. Pat. No. 5,199,325 entitled"Electronic Shift or Clutch Actuator for a Vehicle Transmission" to DanaCorporation; and U.S. Pat. No. 5,303,807 entitled "ElectrohydraulicDevice for Controlling the Engagement of the Clutch in Motor Vehiclesand the Like" to Fadiel.

Some examples of thermal conductors which may be utilized in accordancewith the present invention may be found in the following U.S. Patents:U.S. Pat. No. 5,199,165 entitled "Heat Pipe-electrical InterconnectIntegration Method for Chip Modules" to Hewlett-Packard; U.S. Pat. No.5,243,218 entitled "Cooling Structure for Electronics Devices" toFujitsu; U.S. Pat. No. 5,296,310 entitled "High Conductivity HybridMaterial for Thermal Management" to Materials Science Corporation; andU.S. Pat. No. 5,345,107 entitled "Cooling Apparatus for ElectronicDevice" to Hitachi.

Some examples of seals for electronics components which may be utilizedin accordance with the present invention may be found in the followingU.S. Patents: U.S. Pat. No. 5,278,357 entitled "Electric Wire HoldingCase Preventing Oil Leak" to Yazaki; U.S. Pat. No. 5,326,589 entitled"Method of Protecting Electronic or Electric Part" to Shin-Etsu; U.S.Pat. No. 5,243,131 entitled "Housing for an Electronic Circuit" toBosch; and U.S. Pat. No. 5,282,114 entitled "Ruggedized ComputerAssembly Providing Accessibility and Adaptability to, and EffectiveCooling of, Electronic Components" to Codar.

Some examples of motor current sensors which may be utilized inaccordance with the present invention may be found in the following U.S.Patents: U.S. Pat. No. 5,254,926 entitled "Current-mode HysteresisControl for Controlling a Motor" to Ford; U.S. Pat. No. 5,281,900entitled "DC Motor Controller" to Hyundai; U.S. Pat. No. 5,304,912entitled "Control Apparatus for Induction Motor" to Hitachi; U.S. Pat.No. 5,313,151 entitled "Induction Type Electric Motor Drive ActuatorSystem" to Rotork; and U.S. Pat. No. 5,350,988 entitled "Digital MotorController" to Allied Signal, Inc.

Some examples of devices for testing electronic components which may beutilized in accordance with the present invention may be found in thefollowing U.S. Patents: U.S. Pat. No. 5,289,117 entitled "Testing ofIntegrated Circuit Devices on Loaded Printed Circuit" to EverettCharles; U.S. Pat. No. 5,307,290 entitled "System for the AutomaticTesting, Preferably on a Bench, of Electronic Control Systems Which areIntended to be Fitted in Vehicles" to Fiat; and U.S. Pat. No. 5,315,252entitled "Automotive Test System with Input Protection" to SPXCorporation.

Some examples of optical and other systems which may be utilized with orin the present invention may be found in the following U.S. Patents:

U.S. Pat. No.: 5,280,981, Inventor: Gordon R. Schulz, Title: Endeffector with load-sensitive digit actuation mechanisms; U.S. Pat. No.:5,250,888, Inventor: Hang du Yu, Title: Apparatus for and process ofrotating a display; U.S. Pat. No.: 5,191,284, Inventors: Roberto Morettiand Angelo Varvello, Title: Device for detecting the relative rotationalspeed of two elements in a vehicle wheel; U.S. Pat. No.: 5,239,263,Inventors: Hitoshi Iwata, Katsuhiro Minami, Hisahiro Ando, HisashiHirose and Shigeru Iguchi, Title: Magnetic rotation sensor for rotaryshaft; U.S. Pat. No.: 5,252,919, Inventor: Saburo Uemura, Title:Apparatus producing trapezoidal waveforms from a pair of magneticsensors for detecting the rotating angle of an object; U.S. Pat. No.:5,291,319, Inventor: Ellis D. Harris, Title: Rotating disc opticalsynchronization system using binary diffractive optical elements; U.S.Pat. No.: 5,307,549, Inventors: Seisuke Tsutsumi and Nobuyuki Ito,Title: Apparatus and method for synchronized control of machine tools;U.S. Pat. No.: 5,309,094, Inventors: Christian Rigaux and Pascal Lhote,Title: Bearing rotary speed sensor with concentric multipole magneticrings axially aligned with collector branches; U.S. Pat. No.: 5,192,877,Inventors: Jean Bittebierre and Philippe Biton, Title: Hall EffectSensor and component providing differential detection; Inventors:Shigemi Murata and Masayuki Ikeuchi, Title: Angle detecting devicehaving improved mounting arrangement for mounting Hall-effect sensor.

Some examples of control devices and other systems which might be usedwith or in the present invention are:

U.S. Pat. No.: 4,852,419, Inventors: Friedrich Kittel, Dieter Lutz,Franz Nagler, Horst Oppitz and Gerhard Gasper, Title: Control device, inparticular for a motor-vehicle friction clutch; U.S. Pat. No.:5,212,380, Inventors: Seiichi Sato, Kazuo Yamaguchi, Yoshi Kurosawa,Atsushi Ueda and Masami Matsumura, Title: Automotive engine controlsystem with rotary encoder indexing; U.S. Pat. No.: 5,326,160,Inventors: John P. Bayliss and Sean Byrnes, Title: Hydraulic systems forvehicles; U.S. Pat. No.: 5,307,013, Inventors: Alfred J. Santos andMichael C. Brauer, Title: Digital position sensor system for detectingautomatic transmission gear modes.

Some examples of hydraulic master cylinders which may be utilized inaccordance with the present invention may be found in the following U.S.Patents: U.S. Pat. No. 5,211,099 entitled "Slave Cylinder for aHydraulic Actuating System of a Motor Vehicle Friction Clutch" toFichtel & Sachs; U.S. Pat. No. 5,213,187 entitled "Device Relating to aSemi-automatic Clutch for Vehicles"; U.S. Pat. No. 5,284,017 entitled"Hydraulic Master Cylinder" to Automotive Products; and U.S. Pat. No.5,301,597 entitled "Hydraulic Cylinder" to Kugelfischer Schafer.

Some examples of clutch assemblies and various components associatedtherewith which could possibly utilize the present invention may bedisclosed in the following U.S. Patents: U.S. Pat. No. 4,684,007 toMaucher, entitled "Clutch Plate"; U.S. Pat. No. 4,635,780 to Wiggen,entitled "Clutch Disc for a Motor Vehicle Friction Clutch"; U.S. Pat.No. 4,651,857 to Schraut et al., entitled "Clutch Disc Unit for a MotorVehicle Friction Clutch"; U.S. Pat. No. 5,103,688 to Kuhne, entitled"Two-mass Flywheel"; and U.S. Pat. No. 4,777,843 to Bopp, entitled"Two-mass Flywheel Assembly With Viscous Damping Assembly".

Some examples of hydraulic clutch systems which could possibly utilizethe piston-cylinder arrangement of the present invention are disclosedby the following U.S. Patents, each of which is assigned to the assigneeof the present invention: U.S. Pat. No. 5,211,099 to Grosspietsch etal., dated May 18, 1993 and entitled "Slave Cylinder for a HydraulicActuating System of a Motor Vehicle Friction Clutch"; U.S. Pat. No.5,052,279 to Limbacher and Fadler, dated Oct. 1, 1991 and entitled"Hydraulic Cylinder for a Hydraulic Actuation Arrangement of a MotorVehicle Friction Clutch"; and U.S. Pat. No. 4,456,111 to Limbacher,dated Jun. 26, 1984 and entitled "Hydraulic Control System for aClutch".

Some additional examples of hydraulic and/or pneumatic devices which canpossibly utilize the piston-cylinder arrangement of the presentinvention are disclosed by the following U.S. Patents: U.S. Pat. No.5,092,125 to Leight et al., entitled "Seal"; U.S. Pat. No. 4,635,778 toLederman, entitled "Fluid-Operated Piston"; U.S. Pat. No. 4,960,188 toWossner, entitled "Single-Tube Vibration Damper of Variable DampingForce"; U.S. Pat. No. 5,064,030 to Wossner, entitled "Impact DampingUnit"; U.S. Pat. No. 4,599,860 to Parsons, entitled "Liquid PressureApparatus"; and U.S. Pat. No. 2,317,601 to Fowler on Mar. 7, 1940,entitled "Pressure Braking System".

Hydraulic braking systems which could also possibly utilize the presentinvention may be disclosed in the following U.S. Patents: U.S. Pat. No.4,634,190 to Wupper, entitled "Hydraulic Brake System With SlipControl"; U.S. Pat. No. 4,643,488 to Reinartz, entitled HydraulicVehicle Servo Brake"; U.S. Pat. No. 4,643,489 to Reinartz et al.,entitled "Hydraulic Brake System With Slip Control"; U.S. Pat. No.4,656,833 to Belart, entitled "Hydraulic Brake System for AutomotiveVehicles"; and U.S. Pat. No. 4,902,077 to Belart et al., entitled"Hydraulic Brake System".

The corresponding foreign patent publication applications, namely,Federal Republic of Germany Patent Application No. P 44 33 824.4, filedon Sep. 22, 1994, having inventors Udo Borschert, Lutz Leimbach, UllrichScherpf, Manfred Waning, Michael Zottmann, and DE-OS P 44 33 824.4 andDE-PS P 44 33 824.4, are hereby incorporated by reference as if setforth in their entirety herein.

The invention as described hereinabove in the context of the preferredembodiments is not to be taken as limited to all of the provided detailsthereof, since modifications and variations thereof may be made withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. An actuator for a clutch assembly for a motorvehicle, said actuator comprising:a housing; a mechanical drivemechanism for converting a first geometric movement into a secondgeometric movement; means for driving said mechanical drive mechanism;said driving means being connected to said mechanical drive mechanism;said mechanical drive mechanism having means for being connected to anoutput element for activating and deactivating a clutch assembly; saidmechanical drive mechanism comprising:a worm gear a worm gear wheel;said worm gear wheel being in mesh with said worm gear; said worm gearwheel being disposed within said housing; said worm gear wheel for beingmoved in a first direction and a second direction; said worm gear wheelhaving an outer circumferential portion; said worm gear wheel comprisingat least one notch; at least one member for being engaged within said atleast one notch; said at least one notch having an inner circumferentialportion; said at least one member, engaged within said at least onenotch, having an outer circumference; a portion of said outercircumference of said at least one member engaged within said at leastone notch being in contact with a portion of said inner circumferentialportion of said at least one notch; said inner circumferential portionof said at least one notch being insufficient by itself to hold said atleast one member within said at least one notch; means for retainingsaid at least one member within said at least one notch of said wormgear wheel; and said means for retaining said at least one member withinsaid at least one notch being disposed within said housing.
 2. Theactuator according to claim 1, wherein:said means for retaining said atleast one member within said at least one notch comprises a springstructure; and said spring structure is disposed at least substantiallyadjacent said worm gear wheel.
 3. The actuator according to claim 2,wherein:said at least one notch comprises a first notch and a secondnotch; said at least one member engaged within said at least one notchcomprises a first fastening bolt and a second fastening bolt; said firstnotch comprises means for connecting said worm gear wheel with saidspring structure; said second notch comprises means for connecting saidworm gear wheel to an output element; said first notch for connectingsaid worm gear wheel with said spring structure comprises means fordisposing said first fastening bolt within said first notch; said secondnotch for connecting said worm gear wheel with an output elementcomprises means for disposing said second fastening bolt within saidsecond notch; said means for disposing said first fastening bolt withinsaid first notch is formed from an elastomer material; and said meansfor disposing said second fastening bolt within said second notch isformed from an elastomer material.
 4. The actuator according to claim 3,wherein:said worm gear wheel defines an axis of rotation; said worm gearwheel further comprises a hub; said hub is disposed to surround saidaxis of rotation of said worm gear wheel; said hub generally is formedfrom an elastomer material; said housing further comprises a bearingneck; said actuator further comprises means for connecting said bearingneck to said housing; said bearing neck has one end being connected tosaid housing; said hub of said worm gear wheel is mounted on saidbearing neck; said worm gear wheel is generally formed from an elastomermaterial; and said worm gear wheel comprises a one-piece component. 5.The actuator according to claim 4, wherein:said spring structurecomprises a coil spring mechanism for storing energy; said coil springmechanism for applying a force with respect to said worm gear wheel;said worm gear wheel is rotationally mounted on said bearing neck; saidworm gear wheel has an outer circumferential portion; said outercircumferential portion of said worm gear wheel comprises a plurality ofgear teeth; said driving means further comprising an output shaft; saidoutput shaft has a plurality of gear teeth; said plurality of gear teethof said worm gear wheel are in mesh with said plurality of gear teeth ofsaid output shaft; said driving means further comprising an electricmotor for providing movement of said output shaft; said movement of saidoutput shaft for providing movement of said worm gear wheel; and saidworm gear wheel comprises means for being operatively connected to anoutput element to activate a clutch assembly.
 6. A hydraulicallyoperated clutch assembly for a motor vehicle, said clutch assemblycomprising:means for hydraulically activating said clutch assembly; saidhydraulic activating means comprising means for actuating said clutchassembly; said actuating means comprising:a housing; a mechanical drivemechanism for converting a first geometric movement into a secondgeometric movement; means for driving said mechanical drive mechanism;said driving means being connected to said mechanical drive mechanism; ahydraulic master cylinder; said mechanical drive mechanism having meansfor being connected to said hydraulic master cylinder for activating anddeactivating said clutch assembly; said mechanical drive mechanismcomprising:a worm gear; a worm gear wheel; said worm gear wheel being inmesh with said worm gear; said worm gear wheel being connected withinsaid housing; said worm gear wheel being movable in a first directionand a second direction; said worm gear wheel having an outercircumferential portion; at least a portion of said worm gear wheelcomprising a cut out portion; a spring structure; said spring structurebeing disposed within said housing; said spring structure being disposedadjacent said worm gear wheel; said spring structure having a first endand a second end; said first end of said spring structure comprisingpivot means for permitting pivoting of said spring structure about saidfirst end of said spring structure; said housing comprising mating pivotmeans for receiving said pivot means of said spring structure; saidpivot means of said spring structure together with said mating pivotmeans of said housing permit said spring structure to pivot with respectto said worm gear wheel; said second end of said spring structure beingdisposed opposite said first end; said second end of said springstructure being disposed adjacent a portion of said worm gear wheel;said worm gear wheel being movable in said first direction to disposesaid second end of said spring structure in contact with said outercircumferential portion of said worm gear wheel; and said worm gearwheel being movable in said second direction to dispose a portion ofsaid spring structure within said cut out portion of said worm gearwheel.
 7. The hydraulically operated clutch assembly according to claim6, wherein:said worm gear wheel defines an axis of rotation; a distanceis disposed between said axis of rotation and said outer circumferentialportion of said worm gear wheel; and said cut out portion of said wormgear wheel comprises a substantial portion of the distance between saidouter circumferential portion and said axis of rotation of said wormgear wheel.
 8. The hydraulically operated clutch assembly according toclaim 7, wherein:said outer circumferential portion of said worm gearwheel comprises a first portion and a second portion; said first portionand said second portion of said outer circumferential portion of saidworm gear wheel are disposed to at least partially extend about said cutout portion of said worm gear wheel; said cut out portion of said wormgear wheel is defined by said first portion and said second portion ofsaid outer circumferential portion of said worm gear wheel; and said cutout portion of said worm gear wheel comprises means for preventingcontact between said spring structure and at least one of: said firstportion and said second portion of said outer circumferential portion ofsaid worm gear wheel.
 9. The hydraulically operated clutch assemblyaccording to claim 8, wherein:said first direction of movement of saidworm gear wheel comprises a first predetermined angle of rotation ofsaid worm gear wheel; said second direction of movement of said wormgear wheel comprises a second predetermined angle of rotation of saidworm gear wheel; said housing further comprises stop means forpreventing said worm gear wheel from exceeding a predetermined angle ofrotation; said worm gear wheel comprises an additional cut out portion;said outer circumferential portion of said worm gear wheel furthercomprises a third portion and a fourth portion; said third portion andsaid fourth portion of said outer circumferential portion are disposedto at least partially extend about said additional cut out portion ofsaid worm gear wheel; said additional cut out portion of said worm gearwheel further defines said first angle of rotation and said second angleof rotation of said worm gear wheel; said additional cut out portion ofsaid worm gear wheel is disposed to mate with said stop means; said stopmeans for preventing said worm gear wheel from exceeding said at leastone of: said first angle of rotation and said second angle of rotation;said stop means comprises a pivot stop; said pivot stop is disposedwithin said additional cut out portion of said worm gear wheel; saidpivot stop is disposed substantially between said third portion and saidfourth portion of said outer circumferential portion of said worm gearwheel; said pivot stop has a first end and a second end; said clutchassembly further comprises means for connecting said first end of saidpivot stop to said housing; and said pivot stop for being connected tosaid housing in a stationary manner.
 10. The hydraulically operatedclutch assembly according to claim 9, wherein:said pivot stop has afirst side and a second side; each of said first side and said secondside of said pivot stop comprises an elastomer material; said first sideof said pivot stop further comprises a limit of said first angle ofrotation of said worm gear wheel; said second side of said pivot stopfurther comprises a limit of said second angle of rotation of said wormgear wheel; said worm gear wheel further comprises a hub; said hub isdisposed to surround said axis of rotation defined by said worm gearwheel; said worm gear wheel further comprises a plurality of cheekportions; said plurality of cheek portions comprise a pair of solidwheel portions; said pair of solid wheel portions are disposed parallelto one another; said pair of solid wheel portions are disposed tosubstantially surround said hub; said pair of solid wheel portions aredisposed an axial distance with respect to one another; said springstructure comprises a spring mechanism for storing energy; at least oneof: said pair of solid wheel portions has at least one notch disposedtherein; said at least one notch in said solid wheel portion comprisesmeans for connecting said worm gear wheel to at least one of: saidspring mechanism and said hydraulic master cylinder; and said hub andsaid pair of solid wheel portions together form a single, unitarycomponent.
 11. The hydraulically operated clutch assembly according toclaim 10, further comprising:said means for connecting said worm gearwheel to said spring mechanism comprising a first notch; said means forconnecting said worm gear wheel to said hydraulic master cylindercomprising a second notch; a first fastening bolt for being disposed insaid first notch; a second fastening bolt for being disposed in saidsecond notch; said first notch for connecting said worm gear wheel tosaid spring mechanism comprising means for disposing said firstfastening bolt within said first notch; said second notch for connectingsaid worm gear wheel to said hydraulic master cylinder comprising meansfor disposing said second fastening bolt within said second notch; saidfirst notch having a longitudinal dimension; said second notch having alongitudinal dimension; said spring mechanism for providing a springaction in a predetermined direction with respect to said worm gearwheel; said longitudinal dimensions of said first notch and said secondnotch being oriented in a direction opposite said direction of saidspring action of said spring mechanism, with respect to said worm gearwheel; said spring mechanism comprising a tappet rod; said tappet rod ofsaid spring mechanism comprising a first end substantially adjacent saidfirst notch in said wheel portion of said worm gear wheel; said firstend of said tappet rod comprising an eye; said first fastening bolt forbeing disposed within said eye of said tappet rod; said eye of saidtappet rod comprising means for holding said first fastening boltimmovably and non-detachably within said first notch and thus connectingsaid spring mechanism to said worm gear wheel; said hydraulic mastercylinder comprising a piston rod; said piston rod of said hydraulicmaster cylinder comprising a first end substantially adjacent saidsecond notch in said wheel portion of said worm gear wheel; said firstend of said piston rod comprising an eye; said second fastening bolt forbeing disposed within said eye of said piston rod; said eye of saidpiston rod comprising means for holding said second fastening boltnon-detachably within said second notch and thus connecting said springmechanism to said worm gear wheel; said first fastening bolt beingextrusion-coated with plastic to further hold said first fastening boltwithin said first notch in said wheel portion of said worm gear wheel;and said second fastening bolt being extrusion-coated with plastic tofurther hold said second fastening bolt within said second notch in saidwheel portion of said worm gear wheel.
 12. The hydraulically operatedclutch assembly according to claim 11, wherein:said first fastening bolthas a first end and a second end; said first end of said first fasteningbolt is disposed within said first notch of said wheel portion of saidworm gear wheel; said pair of solid wheel portions of said worm gearwheel further comprises a cover plate; said first notch of said pair ofsolid wheel portions is disposed adjacent and in contact with a portionof said cover plate of said pair of solid wheel portions; said secondend of said first fastening bolt is disposed adjacent and in contactwith a portion of said housing; said first end of said first fasteningbolt being in contact with said portion of said cover plate of said pairof solid wheel portions, and said second end of said first fasteningbolt being in contact with said portion of said housing, furthercomprise said means for non-detachably holding said first fastening boltwithin said first notch of said solid wheel portions of said worm gearwheel; said second fastening bolt has a first end and a second end; saidfirst end of said second fastening bolt is disposed within said secondnotch of said pair of solid wheel portions of said worm gear wheel; saidsecond notch of said pair of solid wheel portions is disposed adjacentand in contact with a portion of said cover plate of said pair of solidwheel portions; said second end of said second fastening bolt isdisposed adjacent and in contact with a portion of said housing; andsaid first end of said second fastening bolt being in contact with saidportion of said cover plate of said pair of solid wheel portions, andsaid second end of said second fastening bolt being in contact with saidportion of said housing, further comprise said means for non-detachablyholding said second fastening bolt within said second notch of said pairof solid wheel portions of said worm gear wheel.
 13. The hydraulicallyoperated clutch assembly according to claim 12, further comprising:abearing neck; said bearing neck being disposed within said housing;means for connecting said bearing neck to said housing; said bearingneck having one end being connected to said housing; said worm gearwheel being rotationally mounted on said bearing neck; said springmechanism comprising a coil spring; said worm gear wheel generally beingformed from a plastic material; a portion of said outer circumferentialportion of said worm gear wheel comprising a plurality of gear teeth;said driving means comprising an output shaft; said output shaft havinga plurality of gear teeth; said plurality of gear teeth of said wormgear wheel being in mesh with said plurality of gear teeth of saidoutput shaft; said driving means further comprising an electric motorfor providing movement of said output shaft; said movement of saidoutput shaft for providing movement of said worm gear wheel; and saidworm gear wheel comprising means for being operatively connected to saidmeans for hydraulically activating said clutch assembly, tohydraulically activate said clutch assembly.
 14. An actuator foractuating a hydraulically operated clutch assembly for a motor vehicle,said actuator comprising:a housing; a mechanical drive mechanism forconverting a first geometric movement into a second geometric movement;means for driving said mechanical drive mechanism; said driving meansbeing connected to said mechanical drive mechanism; said mechanicaldrive mechanism having means for being connected to an output elementfor activating and deactivating the system; said mechanical drivemechanism comprising:a worm gear; a worm gear wheel; said worm gearwheel being in mesh with said worm gear; said worm gear wheel beingconnected within said housing; said worm gear wheel being movable in afirst direction and a second direction; said worm gear wheel having anouter circumferential portion; at least a portion of said worm gearwheel comprising a cut out portion; a spring structure; said springstructure being disposed within said housing; said spring structurebeing disposed adjacent said worm gear wheel; said spring structurehaving a first end and a second end; said first end of said springstructure comprising pivot means for permitting said spring structure topivot about said first end of said spring structure; said housingcomprising mating pivot means for receiving said pivot means of saidspring structure; said pivot means of said spring structure togetherwith said mating pivot means of said housing to permit said springstructure to pivot with respect to said worm gear wheel; said second endof said spring structure being disposed opposite said first end; saidsecond end of said spring structure being disposed adjacent a portion ofsaid worm gear wheel; said worm gear wheel being movable in said firstdirection to dispose said second end of said spring structure in contactwith said outer circumferential portion of said worm gear wheel; saidworm gear wheel being movable in said second direction to dispose aportion of said spring structure within said cut out portion of saidworm gear; said worm gear wheel defining an axis of rotation; a distancebeing disposed between said axis of rotation and said outercircumferential portion of said worm gear wheel; said cut out portion ofsaid worm gear wheel comprising a substantial portion of the distancebetween said outer circumferential portion and said axis of rotation ofsaid worm gear wheel; said outer circumferential portion of said wormgear wheel comprising a first portion and a second portion; said firstportion and said second portion of said outer circumferential portion ofsaid worm gear wheel being disposed to at least partially extend aboutsaid cut out portion of said worm gear wheel; said cut out portion ofsaid worm gear wheel being defined by said first portion and said secondportion of said outer circumferential portion of said worm gear wheel;said cut out portion of said worm gear wheel comprising means forpreventing contact between said spring structure and at least one of:said first portion and said second portion of said outer circumferentialportion of said worm gear wheel; said first direction of movement ofsaid worm gear wheel comprising a first predetermined angle of rotationof said worm gear wheel; said second direction of movement of said wormgear wheel comprising a second predetermined angle of rotation of saidworm gear wheel; said housing further comprising stop means forpreventing said worm gear wheel from exceeding a predetermined angle ofrotation; said worm gear wheel comprising an additional cut out portion;said outer circumferential portion of said worm gear wheel furthercomprising a third portion and a fourth portion; said third portion andsaid fourth portion of said outer circumferential portion being disposedto at least partially extend about said additional cut out portion ofsaid worm gear wheel; said additional cut out portion of said worm gearwheel further defining said first angle of rotation and said secondangle of rotation of said worm gear wheel; said additional cut outportion of said worm gear wheel being disposed to mate with said stopmeans; said stop means for preventing said worm gear wheel fromexceeding said at least one of: said first angle of rotation and saidsecond angle of rotation; said stop means comprising a pivot stop; saidpivot stop being disposed within said additional cut out portion of saidworm gear wheel; said pivot stop being disposed substantially betweensaid third portion and said fourth portion of said outer circumferentialportion of said worm gear wheel; said pivot stop has a first end and asecond end; means for connecting said first end of said pivot stop tosaid housing; and said pivot stop for being connected to said housing ina stationary manner.
 15. The actuator according to claim 14,wherein:said pivot stop has a first side and a second side; each of saidfirst side and said second side of said pivot stop comprises anelastomer material; said first side of said pivot stop further comprisesa limit of said first angle of rotation of said worm gear wheel; saidsecond side of said pivot stop further comprises a limit of said secondangle of rotation of said worm gear wheel; said worm gear wheel furthercomprises a hub; said hub is disposed to surround said axis of rotationdefined by said worm gear wheel; said worm gear wheel further comprisesa plurality of cheek portions; said plurality of cheek portions comprisea pair of solid wheel portions; said pair of solid wheel portions aredisposed parallel to one another; said pair of solid wheel portions aredisposed to substantially surround said hub; said pair of solid wheelportions are disposed an axial distance with respect to one another;said spring structure comprises a spring mechanism for storing energy;at least one of: said pair of solid wheel portions has at least onenotch disposed therein; said at least one notch in said pair of solidwheel portions comprises means for connecting said worm gear wheel to atleast one of: said spring mechanism and said output element; and saidhub and said pair of solid wheel portions together form a single,unitary component.
 16. The actuator according to claim 15, furthercomprising:said means for connecting said worm gear wheel to said springmechanism comprising a first notch; said means for connecting said wormgear wheel to said output element cylinder comprising a second notch; afirst fastening bolt for being disposed in said first notch; a secondfastening bolt for being disposed in said second notch; said first notchfor connecting said worm gear wheel to said spring mechanism comprisingmeans for disposing said first fastening bolt within said first notch;said second notch for connecting said worm gear wheel to said outputelement comprising means for disposing said second fastening bolt withinsaid second notch; said first notch having a longitudinal dimension;said second notch having a longitudinal dimension; said spring mechanismfor providing a spring action in a predetermined direction with respectto said worm gear wheel; said longitudinal dimensions of said firstnotch and said second notch being oriented in a direction opposite saiddirection of said spring action of said spring mechanism, with respectto said worm gear wheel; said spring mechanism comprising a tappet rod;said tappet rod of said spring mechanism comprising a first endsubstantially adjacent said first notch in said wheel portion of saidworm gear wheel; said first end of said tappet rod comprising an eye;said first fastening bolt for being disposed within said eye of saidtappet rod; said eye of said tappet rod comprising means for holdingsaid first fastening bolt immovably and non-detachably within said firstnotch and thus connecting said spring mechanism to said worm gear wheel;said output element comprising a rod; said rod of said output elementcomprising a first end substantially adjacent said second notch in saidwheel portion of said worm gear wheel; said first end of said rodcomprising an eye; said second fastening bolt for being disposed withinsaid eye of said rod; said eye of said rod comprising means for holdingsaid second fastening bolt non-detachably within said second notch andthus connecting said spring mechanism to said worm gear wheel; saidfirst fastening bolt being extrusion-coated with plastic to further holdsaid first fastening bolt within said first notch in said wheel portionof said worm gear wheel; and said second fastening bolt beingextrusion-coated with plastic to further hold said second fastening boltwithin said second notch in said wheel portion of said worm gear wheel.17. The actuator according to claim 16, wherein:said first fasteningbolt has a first end and a second end; said first end of said firstfastening bolt is disposed within said first notch of said pair of solidwheel portions of said worm gear wheel; said pair of solid wheelportions of said worm gear wheel further comprises a cover plate; saidfirst notch of said pair of solid wheel portions is disposed adjacentand in contact with a portion of said cover plate of said pair of solidwheel portions; said second end of said first fastening bolt is disposedadjacent and in contact with a portion of said housing; said first endof said first fastening bolt being in contact with said portion of saidcover plate of said pair of solid wheel portions, and said second end ofsaid first fastening bolt being in contact with said portion of saidhousing, further comprise said means for non-detachably holding saidfirst fastening bolt within said first notch of said pair of solid wheelportions of said worm gear wheel; said second fastening bolt has a firstend and a second end; said first end of said second fastening bolt isdisposed within said second notch of said pair of solid wheel portionsof said worm gear wheel; said pair of solid wheel portions of said wormgear wheel further comprises a cover plate; said second notch of saidpair of solid wheel portions is disposed adjacent and in contact with aportion of said cover plate of said pair of solid wheel portions; saidsecond end of said second fastening bolt is disposed adjacent and incontact with a portion of said housing; said first end of said secondfastening bolt being in contact with said portion of said cover plate ofsaid pair of solid wheel portions, and said second end of said secondfastening bolt being in contact with said portion of said housing,further comprise said means for non-detachably holding said secondfastening bolt within said second notch of said pair of solid wheelportions portion of said worm gear wheel; said housing furthercomprising a bearing neck; said bearing neck is disposed within saidhousing; said actuator further comprises means for connecting saidbearing neck to said housing; said bearing neck has one end beingconnected to said housing; said worm gear wheel is rotationally mountedon said bearing neck; said spring mechanism comprises a coil spring;said worm gear wheel generally is formed from a plastic material; aportion of said outer circumferential portion of said worm gear wheelcomprises a plurality of gear teeth; said driving means comprises anoutput shaft; said output shaft has a plurality of gear teeth; saidplurality of gear teeth of said worm gear wheel are in mesh with saidplurality of gear teeth of said output shaft; said driving means furthercomprises an electric motor for providing movement of said output shaft;said movement of said output shaft for providing movement of said wormgear wheel; and said worm gear wheel is operatively connected to saidoutput element for actuating a clutch assembly.